Lameness is the single most common medical condition affecting horses, resulting in an estimated 600 million to one billion dollar annual loss to the horse-owning public. Typically, lameness evaluation in horses is performed primarily by subjective visual evaluation. For example, an equine practitioner will look at how a horse's head or pelvis moves during a trot to detect and/or diagnose lameness. However, lameness of mild severity can be confusing, and the agreement for subjective evaluation even between experts is poor.
Currently, certain methods and systems have been developed in attempting to achieve more objective evaluation of lameness, but only with limited success. For example, motion analysis systems for detection of lameness in horses, with numerous descriptions, using high-speed video camera, are commercially available. For example, U.S. Pat. No. 6,699,207 to Tasch et al. describes a method of using stationary force plates for the detection and evaluation of horse and cattle lameness. Lameness quantification based upon frequency-based head and pelvic motion has also been investigated.
Another lameness evaluation system developed in France involves the use of accelerometers on the torso to collect body motion data. A fiber optic-based system with wireless data transmission for the visualization of equine movement has been commercially available from Equine Performance Technologies, Inc., located in Oldwich, N.J. However, all of the above mentioned methods and systems are either difficult to implement in the field, expensive, or encumber the natural movement of the horse with excessive or heavy equipment. In addition, although they allow sophisticated data collection, none provide lameness-specific data analysis.
Horses with forelimb lameness will show a “head nod” (or “head bob”), which can be described as the horse's head moving upward during the weight bearing phase of the lame limb and downward during the weight bearing phase of the sound limb. Indeed, this is what actually happens in horses with severe forelimb lameness and what appears to happen to the naked eye during the trot in horses with mild to moderate forelimb lameness. However, due to the rapid movement of the limbs in a horse and the limited temporal resolution of the human eye, these descriptions of the “head nod” are too simple and not entirely correct. Similarly, “hip hike,” “hip drop,” and “gluteal rise” are terms frequently used to describe hindlimb lameness in horses, but these descriptions are also imprecise and incomplete. Objective measurements of head and pelvic movement in lame horses have been made in some laboratory-based, experimental studies.
Therefore, it is desirable to provide a lameness detection and quantification method/system that can measure and evaluate the patterns of vertical head and pelvic motion in correlation with vertical feet movement to detect and quantify lameness in horses. It is also most desirable to provide a method and system to the practicing equine veterinarian in the field that helps in the determination of the specific cause of lameness in a horse.